This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Ongoing research in this project is aimed at characterizing the effects of normal aging on the memory processing functions of the hippocampus and related brain regions in rhesus monkeys. Subjects receive MRI scans and FDG PET imaging annually and the findings are evaluated in relation to signatures of age-related cognitive decline. Naturally occurring reproductive senescence is also tracked in order to test the influence of ovarian steroid decline on the neurocognitive outcome of aging.